2. Marked narrowing of the fissure on attempted adduction with enophthalmos

3. Upshoot and downshoot on adduction

4. Straight or nearly straight head position

5. Sensory status usually normal

IV Simultaneous Abduction

1. Large angle exotropia

2. Face turn to uninvolved side

3. Very limited adduction

4. Simultaneous abduction when looking toward uninvolved side

5. Usually suppresses

Treatment of Duane Syndrome

Each case of Duane syndrome requires a unique approach to treatment, if treatment is even considered.

The Goals of Treatment:(Reasons to treat Duane syndrome)

* Improved head posture

* Elimination or reduction of upshoot and downshoot in adduction

* Elimination or reduction of enophthalmos

* Alignment of eyes in primary position

The Limitations of Treatment:(Appropriate disclaimers)

* Normal ductions and versions cannot be achieved

* Upshoots, downshoots, and enophthalmos can be greatly reduced but not eliminated

* Fusing patient will continue to find areas of diplopia after treatment

* Complaints of diplopia with Duane tend to increase with the patient's age with or without treatment

Principles of Treatment for Duane Syndrome

The treatment of Duane syndrome is surgical. The surgery is aimed at reducing the unwanted effects of co-contraction of the medial and lateral rectus muscles. Successful surgery results in a straighter head position, a lessening of enophthalmos and upshoot and downshoot, and better alignment in primary position. Attempts at improving abduction are less effective and may even be harmful if the lateral rectus is overly tightened because this increases enophthalmos.

Timing of Surgery

The findings typical of Duane syndrome can be observed even in the very young, at a few months of age. Infants are often evaluated to rule out sixth nerve palsy from another cause or simply for esotropia. Surgery can be done at any time, but is usually deferred until the child is walking. Some reasons to consider surgical treatment early are concerns over motor development (walking, catching a ball, etc.), increased stiffness of the lateral rectus, and problems associated with the face turn (both appearance and posture).

Treatment Options for Duane Syndrome (Duane syndrome of the left eye is shown)

TYPE I

1)

Recess medial rectus 3mm to 6mm (8.0mm to 11.5mm from limbus)

2)

Posterior fixation suture to normal medial rectus

3)

Can also recess M.R.

4)

Do not resect L.R.

Vertical recti may be shifted fully to the corner of the lateral rectus of a few millimeters short

1. Recess medial rectus to center (align) the eye - this has no effect on abduction.

2. A posterior fixation suture on the normal medial rectus may diminish adduction innervation slightly in the involved eye making the esodeviation in the involved side less. Because the sixth nerve to the involved lateral rectus is absent, the "laudable secondary deviation" from Hering's law which would enhance innervation to the lateral rectus is not applicable in this situation.

3. Some surgeons have done full tendon transfer of the superior and inferior rectus to the lateral rectus. In all but the mildest cases this procedure may cause more harm than good, by either producing exotropia, increasing enophthalmos, or causing a new, iatrogenic, vertical deviation.

4. Never resect the involved lateral rectus. If done, this can turn a Type I into a severe Type II.

TYPE II

1) XT Duane

2)

1. Recess lateral and medial rectus in the involved eye in proportion. For example: with 15 diopters exotropia in the primary position, 6-8mm LR recession and 4-6mm MR recession.

2. If exotropia is large and enophthalmos is severe requiring a large medial rectus recession, it may be necessary to recess the contralateral lateral rectus to balance the effect of the large medial rectus recession on the affected side.

TYPE III

1) Recess medial and lateral rectus for the enophthalmos, upshoot or downshoot. This procedure is best for more severe cases.

2) A "Y" split of the lateral rectus can reduce tension on the lateral globe lessening upshoot and downshoot.

3) A posterior fixation suture on the lateral rectus lessens "side slip" of this muscle, reducing upshoot and downshoot.

TYPE IV

1) Recess both lateral recti, a larger amount on the involved side even to the extent of crippling this muscle.

2) In cases where the lateral rectus on the involved side has been recessed 10mm or more, and the eye remains exotropic, the antagonist medial rectus may be resected.

This type of Duane is rarely encountered. It requires a surgical approach designed for the unique problem at hand.

Duane Syndrome Summary

Duane syndrome is often hereditary and is common. It is easy to diagnose because of the face turn and is confirmed by noting limited abduction of the involved eye with narrowing of the fissure on adduction. This can occur with or without upshoot and downshoot. This diagnosis is usually made before school age. Duane syndrome patients can have good fusion provided they assume a face turn. Diplopia is usually experienced in other fields. Treatment is indicated for anomalous head posture or for the effects of co-contracture, enophthalmos, upshoot or downshoot. Younger children do not complain with Duane syndrome. In contrast, adults will complain bitterly of both the cosmetic problems created by Duane syndrome and the intermittent diplopia. When surgery is done, expectations should be realistically limited. From a practical point, a school-age child with Duane I would do better seated in the classroom in a location where most of the activity would be taking place to the side of the classroom where the child has better ocular motility, left Duane I left, right Duane I right.